James f



(No Model.)

. J. P. DUFFY.

REHEATING FURNACE.

Patented Feb. 21, 1882 illUEllTEl 1 WITIIEEEIEE I Shx 3 a N. PETERS Pnohrljlhagnpher. wnshinmun, D. c.

UNITE STATES PATENT- OFFICE.

JAMES F. DUFFY, OF SOUTH CHICAGO, ASSIGNOR OF ONE-HALF TO AUGUS- TUS D. LAMB AND FRANCIS W. NEWLAND, BOTH OF CHICAGO, ILL.

REHEAT lNG-FURNACE.

SPECIFICATION forming part of Letters Patent No. 253,916, dated February 21, 1882.

7 Application filed June 13, 1881. (No model.)

To all whom it may concern:

Be it known that I, JAMES F. DUFFY, acitizen of the United States, residing in South Chicago, county of (look, and State of Illinois, have invented a certain new and useful Reheating-Furnace, of which the following is a specification.

This invention relates to improvements in furnaces for reheating iron or steel bars, tools,

&c., and in which said bars and tools are.sus-

trating, instead of diffusing, the heat is to heat.

to a high degree that portion of a steel bar'or tool directly over the tuyere, while other portions of the bar remote from the tuyere remain at comparatively a low temperature, and as a result the temper of the bar or toolis rendered variable, and its quality consequently deteriorated. Skilled labor has been employed to more the bar back and forth, or to manipulate it so as to as far as possible evenly heat it; but this mode of operation is not only expensive, but not altogether successful.

The object of my invention is to avoid these objections by providing means for evenly distributing the blast of air from the tuyeres or air-pipes before comin g in contact with or penetrating the fuel or products of combustion in the fire -chamber, and thereby promote combustion and cause a uniformity of and even distribution of the heat generated over the entire surface of the fuel and area of the firechamber, so that the bars or tools to be treated will be evenly heated without requiring any manipulations or change of place in the furnace. Iattain these objects by devices illustrated in the accompanying drawings, in which- Figure lis a perspective, with parts broken away, of a furnace embodying my invention;

and Fig. 2, a vertical longitudinal section of the same.

Similar letters of referenceindicate the same parts in the figures of the drawings.

A represents the front,.B the rear, and G O the side walls, of my furnace, which is provided with an arched or reverberatory top, D, provided with perforations d, to permit unconsumed gases to escape, said walls and top be-' ing of the ordinary construction, and of brick or other suitable material.

In the front end and toward the top of the furnace is a vertically-sliding door, E ha ving So far the furnace described is of the construction ordinarily used for reheating bars of iron, steel, and a variety of small tools, except that usually a ledge is formed above the surface of the fuel for supporting the latter articles and the ends of the bars but as my object is to diffuse or spread the blasts of air, and consequently the heat over the entire firechamber, 1 provide an open rectangular and perforated fire-box, K, which, when in use, is filled 'with coke, coal, or other suitable fuel. This firebox is of less dimensions than'and is supported above the bottom and from the sides of the furnace, so that a surrounding air space or chamber, 70, is formed for the free circulation and spreading out of the blasts of airbefore entering the box. The perforations are of sufficient size to permit a free circulation of the air through them and extend over the entire bottom, butthose upon the sides and ends are preferably near the bottom, as shown, so that the blasts of air will be caused to enter the fire-chamber below the surface of the burnin g fuel, it being understood that the air-pipes or tuyeres will deliver the blast upon the outside of andbetween the perforations in the box, so that the blast will be spread out, and circulating through the chamber will then pass through the perforations to the fuel.

The top of the air-chamberis closed by arim or ledge, 1, connecting the upper edge of the fire-box which rises to a level with the f urnace-door with the walls of the furnace, said ledge forming a shelf or support for the ends of the bars and for small articles to be reheated.

Below the bottom of the fire-box, and dividing the air-chamber at that point, is a perforated plate, M, conforming in area to the bottom of the fire-box, and having its perforations m an alternating with those in the bottom of the fire-box, as shown in Fig. 2, so that currents of air which may be introduced through the openings a a in the front of the furnace and below the plate, or through air-pipes, will be divided and difiused over the entire bottom before passing through the fire-box.

From the above description it will be understood that by thus dividing and spreading out the currents or blasts of air uniform combustion isproduced throughoutthe entire contents of the firebox, and consequently an even temperature is maintainedin theeombustion-chamber, which is that portion of the furnace above the surface of the fuel, and particularly at that portion of it where the bars or tools are placed.

As before stated, the result of having such an even temperature is to entirely do away with any necessity of skilled labor for manipulating the articles, and, moreover, of watchin g them further than to determine when they have attained the desired heat.

The fire-chamber and plate just described to illustrate myinvention are constructed of plate metal; but I wish it to be understood thatI do not limit myself to this particular material, for it is obvious that the equivalents of said chamber and plate may be built of brick, and the openings or perforations be formed by houeycombing the same, without departing from the spirit of my invention, the main object in either construction being to spread the heat, so that the bars and tools will be evenly heated throughout their dimensions.

What I claim, and desire to secure by Letters Patent, is-

1. The combination in reheating-furnaces, with a perforated fire-box, having a perforated plate arranged below and between said firebox and the tuyeres to obtain an even distribution of heat, of a surrounding ledge to receive the articles to be heated.

2. A heating-furnace consistiu g of the perforated fire-box, the furnace-walls, an air-chamber surrounding said fire-box, and air-inlets enterin g said chamber, as and for the purpose set forth.

3. A reheating-furnace consisting of the perforated fire-box, the air-chamber surrounding said box, the air-inlets of a perforated plate arranged below a n til b e;t wm said firebox and the tuyeres, ant said tuyeres, substantially as and for the purpose set forth.

'JAMES F. DUFFY.

Witnesses:

J NO. G. ELLIOTT, JAMES H. OoYNE. 

